20 



Generating Economic Cycles 



Figure 4 



Secular trends in the index numbers of the yield and price of corn and wheat. 



Corn: Yield, y = 103.9 + .838x — .0032x2 — .002,233x', origin at 1899; 



Price, y = 102.4 + 1.690x + .2275^2 _ .001,288x3, origin at 1897. 



Wheat: Yield, y = 102.1 + .952x — .0004x2 — .OOl.lOlx^, origin at 1899; 



Price, y = 99.2 + 1.057x + .1780x2 - .005,570x3, origin at 1897. 



to the data, and the resulting equations were found to 

 be those that are given in the descriptions of Figures 

 4, 5, and 6. The origins of the equations are different 

 in the two graphs, because the crops are taken from 



